1. Field of the invention
The present invention relates to an antenna structure, and in particular, relates to an antenna structure with a changeable operation band.
2. Description of the Related Art
There are different operation bands, in different areas, for a single wireless communication standard. For example, in America, the operation band of the Long Term Evolution standard is between 704˜960 MHz and 1710˜2170 MHZ, and in Europe, the operation band of the Long Term Evolution standard is between 791˜960 MHz and 1710˜2170 MHZ. However, along with decreased dimensions of wireless communication devices, the dimensions of the antenna structure have been reduced, restricting the range of the bandwidth of the antenna structure. Particularly, the low frequency band portion of the antenna structure cannot simultaneously satisfy the transmission requirements of the American standard and the European standard.